oe oslo



Patented Aug. 16, 1927.

UNITED STATES PATENT OFFICE.

MATHIAS OVROM SEM, OF OSLO, NORWAY, ASSIGNOR TO DET NORSKE AKTIESELSKABFOR ELEKTROKEMISK INDUSTRI OF NORWAY, OF OSLO, NORWAY.

PROCESS OF BUILDING UP SELF-BAKIN G "ELECTRODES.

No Drawing. Application filed scp tc l l 2 1925, Seri l N o.'58,850, andin Norway October 4, 1924.

The present invention relates to electrodes being baked in the furnacein which they are used, and the object of the invention is a processwhereby such electrodes are built up 5 in a simpler and more practicalway than heretofore known.

In most of the stationary carbide and ferro-alloy furnacesthe buildingup of the electrode-sections is effected by welding a new section to themetallic mantle which en- 'closes the electrode mass,'and filling thenew sctionwith raw elect-rode mass. The operation is carried out inaclosed room above -.'the furnace. In furnaces arranged for tilting, asfor instance steel furnaces, and in plants where the space above thefurnace is too small for building a tamping-house, this method ofconnection cannot conveniently be used. I have now found that in suchfurnaces the connection ,may conveniently and safely be effected byplacing a previouslyprepared section of raw electrode mass on the top ofthe electrode to which it is to be connected, and connecting as belowdescribed. This enables the preparation of such raw electrode sectionsoutside the furnace in which they are to be employed, as for example atelectrode factories, and transporting the same to their place of use. I

I am aware of previous experiments of connecting prebaked carbonelectrodes by giving their ends a suitable form and coating with tar orelectrode mass. It has, however, proved impossible to attain a stableconnection between a prebaked electrode and raw electrode mass which isafterwards baked on the electrode. By connecting prebaked electrodes, noother contact is therefore obtained than that which is due to the shapeof the end pieces. They cannot be pasted together by means of rawmass.The only effective connection between two baked carbon or graphiteelectrodes is therefore -one with thread and nipple. With unbakedelectrodes, however, an excellent connection may be attained by pasting. If the electrode mass contains sufficient binder, it will at100-200 C. be semi-liquid and between two sections of such mass acompletely homogeneous connection will be formed, especially if the massis subjected to pressure during the baking. When using selfbakingelectrodes, care should be taken to keep the upper end of the electrodeas raw as possible when a new section is to be connccted'thereto.According to my present in vention, I makev complete electrode-sections,well tamped or pressed, at some convenient place, and then bring them.to the furnace in which they are to be used. I thus avoid the tampmg ofthe electrode mass in or above the electric} furnace and at the sametime have the advantage of being able to employ the Inostelfectivemachinery and tools for pressing of tamping the mass. In cold state themass is'hard and little movable relatlyely to mantle and suchmantle-sections w th raw mass may, therefore, be subject to trade andtransport in the" same way as usual electrodes The connection betweenthe electrodesections will be just as-good as by continuous tamping ofelectrode mass into the mantle at the place where it is used.

The electrode-sections may consist of raw electrode 'mass 'alone or rawelectrode mass w th a' metal armatiire, such for, instance, as ametallic casing or mantle enclosing the raw mass. Thiscasi'ng'may' againbe prov ded with radial ribs penetrating into the mass as is'w'ell knownin the art; The mode of building up an electrode from such sectionsvaries slightly according to the nature of the'metallic armature of theelectrode in quest on. -Electrodes in which the external mantle 1swi'thoutribs'may be built up by placing a new mantle-section filled withraw mass on top of the electrode in use. The mantles may be weldedtogether end to end, or may telescope slightly, the new sectionpreferably entering a little into the -old one, which should then not becompletely filled with original electrode mass. As soon as the newsection is sufliciently heated the mass is rendered movable relativelyto the mantle and will sink towards the mass in the electrode below. Tobe quite sure of a complete incorporation, some hinder or raw mass withmuch binder preferably heated may be placed between the electrodes. Mostselfbaking electrodes have besides an external mantle also radial ribsor other metallic reinforcement penetrating into the electrode mass. Themethod of connectin will then be as follows: The armature may e made asdescribed in foreign patent applications by Jens lVestley, of commonownership herewith, as follows:

Norway, No. 25,614, filed January 12, 1922; Finland, No. 2,255, filedJanuary 31,

1923; Sweden, No. 3.154/23, filed November i 1923; France, No. 180,147,filed November 14, 192?); Canada, No. 283,035, filed December 14, 1923.

The ribs then only project at one end of the mantle-section, and at theother end working openings should be arranged for welding the ribstogether. Or, in all sections the ribs are longer than the mantle, theends of the ribs projecting, for instance, centimeters beyond themantle. The mantleis .ta nped full of electrode mass, but the ends ofthe ribs remain free. The connection may be carried out above theelectric furnace in which the electrode is used or the short electrodein useniay be lifted out of the furnace. for connection. The new sectionis brought in place so as to make the rib-ends of both sections meet andthe ribends arethen connected by welding or screwingr Raw-electrode massis then tamped around the ribs and the openings are closed trodesections of raw electrode mass outside the furnace in which they are tobe employed, and connecting said sections to the non-working ends ofpartly used electrodes.

2. .The process of building up selfbaking electrodes which comprisespreparing electrode sections of raw electrode mass outside the furnacein which they are to be em ployed, and connecting said sections withadditionalraw el ctrode mass to the non working ends of partly usedelectrodes.

3. The process of building up selfbaking electrodes provided withmetallic armatures which comprises preparing electrode sections of rawelectrode mass enclosed in metallie arniatures outside the furnace inwhich they are to be employed, and connecting said sections to thenon-working ends of partly used electrodes of similar character.

4. The process of building up selfbaking electrodes provided withmetallic armatures which comprises preparing electrode sections of rawelectrode mass enclosed in metallic armatures outside the furnaceiii-which they are to be employed,"an'd electrically and mechanicallyconnecting said sections to the non-workingendsoi p'aitly usedelectrodes of similar ch aracter.

5. The pro'css'of' building up 's'e lfba'kiiig electrodes provided withmetallic armatures and metallic reinforcementswhich comprises preparingelectrode sections o'traw electrode mass enclosed i n metallic. aiii'iatures and pro-'- vided with ,metallic reinforcements outsideof thefurnace in which they arepto be em ployed, and electrically andlnechariical ly" connecting the .respectiie armaturesa'nd reinforceme'ntsofrsaidl sections to the-cone sponding paijts of the non-working' partlyused elcctrodes ot s irnilar character.

6. The-process of buildihgiup" selfbaking" electrodes provided withm'etallic'a'i matures having radial which 'co'mprises"prepar .ingelectrode ectionsl of 'raw electrode ma's 39 enclosed, in ch metalliciii-matures outside ofthe furnace fin wliiclifthey 'are f to jbe' employed, electrically and iie'chanieally con necting :the ',res jective'iarniaturs and ribs of saidiseetions" to' t he. c o i of the"non-working end partly 'iised electrodes of 's'ifm ilaizfch -:i ractei',and enn et ing thefraw electrode mass foffitli'e: sections preparedoutside" of; the '.s'aid furnace w itli" additional :raw electro t-rodeniass ofiheinoni "orking ends of said" Partly used electrode/sf 7. Theprocess ot' building selfb'a ki'ng electrodes provided with metallicarmatures having radial ribsf w liich 'coiiiprise's eeper 9s ingelectrodeseetions of raw electrodeina'ss enclosed in such metallicarmaturesputsitle" the furnace in which they are tdbe' em:- ployed,electrically and mechanicallycon-' meeting the respective arm'aturcs andribso f said sectionsto the hoi'responding'parts'of thenon-working'erids of partly ,used 'elec trodes of similar character, andconnecting the raw electrode mass of said sectionspre pared outside ofthe said furnace to the electrode mass of the non-working ends ot saidpartly used electrode by meansof additional raw electrode mass by theapplication of heat-and pressure thereto.

Signed at New York, N. Y.,'Sept. 22nd;

MATHIAS OVROM SEM.

endear di P 3

